Watching a professional on television can make drywall finishing look quick and easy. In actuality, drywall finishing takes a lot of practice; and unlike the people on TV, most of us don't have years of experience (or the luxury of editing).
Learn from the Pros
Now that you've installed the drywall (what some would call the easy part), it's on to the next step. While a video or book can tell you the basics of drywall finishing, the technique is really something that should be relayed in person. Since you'll probably have to buy supplies anyway, consider purchasing them from a professional supplier. It might be a bit more out of the way than the local hardware store, but the advice on what tools to use and how to use them is worth the trip.
Drywall Finishing Tools
Most drywall jobs require a combination of tools. You'll most likely need some or all of the following for every job: a bucket for mixing joint compound, both a drywall and finishing knife, a pan to hold joint compound, a roll of drywall tape, and a sponge for wet sanding.
Drywall Finishes
There are two basic finishes drywall can have. A textured finish is considered the easiest to achieve because small mistakes blend into the texture and look natural. This kind of finish is very good for walls that have taken (or will take) some abuse. You don't have to worry if your wet sanding technique isn't perfect. Corners, which are tricky, become less of a hassle, as do the spot marks over nails or screws. Depending on the level of texture and how well you've used your knives and tape, you might not have to sand at all!
Professionals charge more for smooth finishes, and for good reason. Drywall finishing takes on a whole new dimension when a smooth finish is called for because it requires a lot more work, as well as a very strict attention to detail. Joints have to be taped just right. If a mistake is made, it often has to be redone from scratch to keep the surface even. Screw holes must be filled and sanded (though a professional should be able to do this with many screws at a time). Since smooth drywall finishing is so touchy, it's not recommended for beginners (unless they have a lot of time to kill).
Drywall Finishing over Holes
It takes a little practice to get good at filing in small holes and dents in drywall, especially if you are dealing with a smooth finish. With a bit of effort, and some time, however, anyone can learn to fix these small contusions. On the other hand, repairing a hole large enough to require a patch is in a league of its own. This is where drywall finishing becomes an art. Patch kits can be purchased at any hardware store, but the directions on the back are simply no match for a time-tested hand. DIYs beware! Know beforehand that it might take a few tries before you get it right, and years before you can get it right quickly.

Jon Nunan is a freelance writer who draws on his experience in construction, ranging from landscaping to log home building, for his articles on home improvement.